Quote Originally Posted by viperwasp View Post
I am just trying to understand why we have NEVER seen the sharingan share vision like this ever before? It has to be because of the fact that Kakashi just killed or mortally wounded someone so close to him.
Probably because
A) Between the 5 main characters up to this point, nobody else shares a sharingan
B) Hashirama cells, vicinity, and the scale of the event

All talk of this releasing the MS I dunno, could be possible but Kakashi doesnt show his for another 15 years, and Madara already hinted that Obito might already have it. Of course killing your best friend isn't the only way, eyes can't determine who your best friend is. Just like how EMS was originally obtained from taking your brothers eyes and was later retconned to brothers being the most compatible